1. Field of the Invention
The present invention relates to a rotary magnetic head device for a magnetic recording/reproducing apparatus and, more particularly, it relates to a rotary magnetic head device including a dynamic pressure type bearing suitable for controlling a gap between rotary transformers or transmitters.
2. Related Art Statement
Heretofore, a rotary magnetic head device for a magnetic recording/reproducing apparatus has been so constructed that a rotary shaft of the head device is supported by two ball bearings and a preliminary pressure is applied axially to the ball bearings so as to maintain the shaft in position at a high accuracy.
With the above construction, a transmitter is provided on each of an upper rotatable cylinder and a lower stationary cylinder of the magnetic rotary head device, in order to transmit an electric output from the rotary magnetic head to a stator without causing any contact therebetween. It is necessary to set a gap between the transmitters constant at a high accuracy. Generally, the gap is set on the order of several ten microns. If the gap is too large, the efficiency of the transmission of the electric signal would be lowered. On the other hand, if the gap is too small, contact between the transmitters might occur resulting in variation in the speed of rotation.
As disclosed in Japanese Patent Laid-Open No. 56-22215 and Japanese Patent Laid-Open No. 56-20829, a construction has been proposed in which rotary transmitters are formed in a cylindrical shape so that the signal transmitting characteristics of the rotary transmitters are not deteriorated even though the accuracy in the adjustment of the axial positions of the rotary transmitters is lowered to some extent. In this case, however, problems arise that the control of the gap between the transmitters is not easy, because it becomes necessary to sufficiently control the accuracy of working and assembling of the rotary transmitters.